In a box-erecting or packaging operation as described in German patent publication 100 65 310 of R. Stahn a flattened box blank is typically pushed into a tubular three-dimensional having two oppositely open sides from each of which several flaps extend. Then two flaps at one of the open sides are folded in and pressed together, normally after applying a contact adhesive to that face of one of the flaps that bears against the other flap, typically the outer face of the inner flap. This creates a stable three-dimensional box that can be tipped up on the now closed side formed by the glued-together flaps, and then filled through the other side that is upwardly open.
Other apparatuses for folding in and gluing flaps are described in German patent publication 1j99 18 940 of R. Ruf and U.S. Pat. No. 5,369,933 of M. Waldstädt. These devices are all fairly complex. None of them allows a flap to be pivoted gently from a position projecting outward through a box through 90° to a position bearing against the glue strip of the box by a relatively simple mechanism. Furthermore changing the operation of the box-closing apparatus to accommodate a box of different size is very difficult with the prior-art machines.